Solving the World energy crisis.

Take an old warship and allow the tide to raise the huge vessel in the air and build a tower to hold it there when the tide retreats. Use the weight of the vessel to drive a turbine and create electricity. The tide will raise it twice a day. These can be placed all around the coast and could be lumps of concrete camouflaged as pretty houses or rocks but you get the idea. An alternative way of using the power of the tide without having to block estuaries etc. Please can someone tell me why this won't work? probably obvious...

Jun 10 2014:
Hello Carl - Many thanks for taking the trouble to reply and I agree with all of your points. A quick search has told me that between 44 and 50% of the World population lives within 60Km of a coast so in principle the logistics might be worth while versus say wind power. I don't have the knowledge to work out how much energy we might get from raising perhaps 35,000 tons through say 10 metres. I envisage old warships or even blocks of concrete designed to look like houses being within existing harbours or in sheltered bays which would help re the storms. In suitable areas piles might be driven into the ground to take the weight. I agree that tides are variable but they are predictable with some accuracy which is also better that wind or even wave power which also relies on the wind. Tidal flow barriers are also an engineering nightmare and potentially bad for the environment. Thanks again,

Jun 10 2014:
In theory, this raising and lowering of a large ship by tidal power could be used to generate electrical power. And, in theory, theory and practice are the same, but in practice, things might be quite different - they usually are. A lot of engineering would need to be done to try to devise a practical and economical system.

There would be variability of tide heights to deal with, because tides at any particular location do vary, so the amount of power generated would likewise vary. In many areas, there isn't much variation between high and low tide, so power generating potential would be limited - possibly too limited to justify the expense of setting it all up and operating it. In other places, tide variation would be greater, but then so too would be the challenges of designing a cost effective and reliable system. The whole operation would need to be able to weather storms, especially hurricanes/cyclones, that could disrupt the whole system at great expense or even total loss.

Tides, of course, only occur along ocean coasts, and transmitting power far inland to mid-continent areas would be inefficient. But if feasible systems could be designed and economically built and operated they could supply much of the power required along coastal areas.

Tidal power would only be produced twice a day, on a varying schedule. Power demands vary according to human needs on a pretty regular diurnal cycle. That means that some system would need to be used to store energy when it is produced so it can be used when it is needed. Power storage is always a huge challenge. It's one of the challenges that has limited development of solar power.

Jun 3 2014:
The raised ship has a lot of potential energy since it is sitting in a gravitational field but in order to release it you must allow the ship to sink under its own weight, then it can turn a turbine and generate electricity. Once in the lower energy state, that is resting on the beach say, it cannot generate any more electricity. Then it must wait for the tide to raise it again to a higher level so it may sink again etc. This approach, although in a different form is being used in various forms already, hydroelectric power stations use the same approach except they use the weight of the water behind a dam to turn a turbine as the water rushes down the energy incline. Wave power attempts to make use of the energy present in water, the tides, to extract energy as well.

Thanks for taking the time to reply. I agree with your comments but still need to be persuaded that the ship/tide idea does not have merit as a reliable twice a day convenient application which should not affect the environment much.

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